fix: manifest serialization issues

[antazoey]

What I did

attempting to fix your issues @Ninjagod1251 but also took some time to utilize pydantic 2.0's field serializers rather than overriding model_dump() which is a much better practice.

How I did it

How to verify it

Checklist

• [ ] Passes all linting checks (pre-commit and CI jobs)
• [ ] New test cases have been added and are passing
• [ ] Documentation has been updated
• [ ] PR title follows Conventional Commit standard (will be automatically included in the changelog)

[antazoey]

btw i have confirmed this fixes the issue in hosted compiler